Rust preventive composition



United States Patent RUST PREVENTIVE COMPOSITION Michael J. Furey, Berkeley Heights, N. J., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application March 5, 1956 Serial No. 569,253

6 Claims. (Cl. 106-14) This invention relates to improved rust preventive compositions and, more particularly, to improved compositions having utility as solvent-cutback, hard film rust preventives. More specifically, the invention relates to asphalt cutback rust preventive compositions which have been stabilized against viscosity change during storage by inclusion therein of a minor proportion of a wax-substituted glyoxalidine.

Solvent-cutback, hard film rust preventives are known in the art. These are cold-applied compounds used for (l) the protection of metals exposed to a variety of outdoor weather conditions and (2) any general purpose preservation where a dry-to-touch film is desired. These materials generally contain an asphalt diluted with a petroleum solvent. The compounds are fluid in nature and may be applied to the metal surfaces to be pro tected by dipping, brushing or spraying. Upon evaporation of the solvent, a thin film, usually 0.0020.004 inch thick, remains on the metal parts to serve as protection against Weathering, corrosive fumes, and the like. In addition, the protective coating should not flow from the surfaces at high temperatures nor flake at low temperatures. When desired, the thin film is easily removed from the metal surfaces by the application of solvents such as petroleum solvents and the like.

Asphalts made by air-blowing or oxidation processes may be desirable as base materials for use in certain solvent-cutback, hard film rust preventives because these asphalts can be made to have a high softening point without being brittle at low temperatures. Accordingly, compounds based on these asphalts have less of a tendency to flow from metal surfaces in hot weather or to flake from metal surfaces when cold. However, solvent-cutback, hard film rust preventives made from these high softening point oxidized asphalts tend to increase in viscosity, thicken, and eventually gel on storage. This is particularly undesirable since the application of the rust preventive by dipping or spraying is'made'difiicult or even impossible. Furthermore, the thickness of the film deposited upon the metal parts with the thickened or gelled material is considerably in excess of that desired.

It has now been found and forms the object of this invention that this undesirable thickening effect or gelling may be inhibited by the inclusion in these solventcutback, hard-film rust preventive compositions of a minor amount of a wax-substituted glyoxalidine compound.

The base material for the compositions of this invention comprises from 30 to 70% by weight of an asphalt and from 70 to 30% of a solvent therefor. The asphalt may be selected from the group-of oxidized asphalts, or reduced and oxidized asphalts, with the former being preferred. Especially preferred are oxidized asphalts having a softening point between about 180 and 235 F.

The solvent used in preparing the base material may be any of the well-known petroleum solvents having flash points between about 100 and about 150 F. and midboiling points ranging from about 300 to about 350 F.

2,860,996 Patented Nov. 18, 1958 with a final boiling point below about 420 F. If it is desired, blends of various solvents may be made to use as the diluent for the asphaltic material.

The storage stability of asphalt cutbacks varies, to some extent, with (l) the concentration of asphalt (i. e., the more asphalt, the less stable), (2) the nature of the asphalt (oxidized asphalts gel moree readily than straight reduced asphalts, and high softening point oxidized asphalts have the poorest stability), and (3) the nature of the solvent (e. g. cutbacks made with'parafiinic solvents gel more than those made with aromatic solvents).

For adequate protection against corrosion under a wide variety of outdoor exposure conditions, the protective coating should be at least 0.002-0.004 inch thick. To accomplish this by a single dip or immersion of the metal in the rust-preventive, the concentration of the asphalt must be high enough (preferably 40-60%). At these concentrations, a serious storage stability problem exists. Storage stability with oxidized asphalts in the required concentration, would generally be:

(1) Very, very poor with the more paraffinic solvents (e. g. hexane).

(2) Better but still very poor, with solvents containing about 20% aromatics.

(3) Better yet with a highly aromatic and expensive sol- ,vent such as those containing in the neighborhood of aromatics.

It is preferable to use as much paratfinic solvents as possible for economic reasons.

In accordance with the concept of the instant invention, the storage stability of all cutback asphalts from oxidized asphalts is improved without adversely affecting any other desirable properties of a good solvent-cutback rust preventive.

' According to the invention cutback asphalts are blended with from 1 to 5 wt. percent of a wax-substituted glyoxalidine compound having the general formula:

/NCH2 R-c III-CH (mmNHnH wherein R is a monovalent saturated hydrocarbon radical having from 40 to 80 carbon atoms and wherein x is a number of from 1 to 2. A compound according to the formula above, when x is 1 and the average carbon content of the wax hydrocarbon radical R is 50, is available commercially under the trade name Petrolite, Wax Amine B.

In accordance with the concept of the instant invention, a solvent-cutback, hard film rust preventive base composition (Base A) was formulated from the following components:

(1) The asphalt used was an oxidized asphalt made by the pipe still reduction of Venezuelan (Lagunillas) Crude to 500/505 F. flash point stock followed by oxidation by air-blowing to 229 F. softening point. Its properties were as follows:

(a) Penetration,(cm.

32 F. (200 g./60)13 77 F. (100 g./5)21 F. (50 g./5)--28 (b) Ductility 77 F.=2.3 cm. (c) Pliability:

0 F.=9 77 F.= 118 (d) 99.90% soluble in carbon disulfide (e) 41.0% insoluble in 86 naphtha (1") 15.88% fixed carbon Distillation range:

50% off 340 F. 90% ofi 375 F. F. B. P., 385 F.

Solvent II is an aromatic petroleum solvent having more than 95% aromatics and the following inspections:

Flash point=l07 F.'

Distillation range:

Initial boiling point, 300 F. 50% olf @350 F., 90% off 350 F. F. B. P., 370 F.

(3) The, plasticizer used consists of. a mixture of phenol extracts from Coastal lubricant distillates. This mixture has an open cup flash point 435 F. and an S. U. S. viscosity of 240-260 210F.

(4) The Wetting agent is the salt of Armeen T (a primary fatty amine made by Armour. and Company consisting of 30% hexadecylamine,,25% octadecylamine, and 45% octadecenylamine) and oleic acid.

These components, were blended in the followingproportions:

Weight percent Base A:

Oxidized asphalt 47.2 Petroleum solvent 47.2. Plasticizer 4.7 Wetting agent 0.9

The storage stability of this base material (Base A) alone and containing 2 Wt. percent of the Wax-glyoxalidine compound according to the formula above, R being 50 and x being 1, was subjected to the Federal Specification MIL-C-6708 storage stability test. This test is run as follows:

Test panels made of steel are prepared and polished with a 280 grit medium. The panels are 2 by 4 inches in width and length respectively, and from A to /s" in thickness. Immediately prior to use, the panels are cleaned by successive washings in various solvents, ending finally with absolute methanol.

Two steel panels thus prepared are then weighed to' the nearest milligram, and the rust preventive compound is applied by dipping at 70 F. Each test panel is totally and vertically immersed in the rust preventive compound for one minute and withdrawn from the compound at a rate of 4 inches per minute, employing a Fisher-Payne dip coater. The coated panels are allowed to dry for 24 hours at room temperature and then reweighed to the nearest milligram. The average film thickness is then calculated from the weight of the film, its density and the total surface area of the test panel. The rust' preventive is then stored for 1 month at room temperature in a round l-quart friction-top can which is tightly closed and sealed with tape. After storage, the can is rolled for about 5 minutes for mixing and then opened. Film thickness determinations are then carried out again as described above and the percent increase in film thick ness is calculated. Compounds having film thickness increases greater than 10-l5% in 1 month are considered poor with respect to storage stability.

The data obtained on the base material and the material prepared in accordance With tho invention are set out in Table I below:

1 Final boiling point.

TABLE I Storage stability of solvent-cutback, asphalt base rust preventives Gelling Tendency I (MIL-0*6708) Storage Stability 21 days 30 days 72 days Percent Percent Percent BaseA 21.2 22.8 33.7 Poor. Base A+2.0 Wt percent of wax-substituted glyoxaiidine 3.1 4.1 6.7 Very good.

1 Percent increase in film thickness after compound is stored.

After about one year of storage at room temperature, it was found that the composition containing the waxsubstituted glyoxalidine was still fluid, whereas the base material (Base A) had gelled to a semi-solid.

It is to be seen that the inclusion of the wax-substituted glyoxalidine greatly improves the storagestability of the thin film rust preventive composition.

In addition to being an excellent rust-preventive, it was found that the'composition containing the wax-substituted glyoxalidine was also satisfactory from the standpoint of drying time, film continuity, flow at high temperatures and low temperature adhesion as shown below:

Other properties: of the' rust preventive composition containing 2 wt. percent'wax-substituted glyoxalidine Property Periormanceoi the Composition Drying Time 1 4 hours:(Good).: Coating Appearance Smooth and continuous.

Low Temperature Adhesion fin ches halting- 0 $62 (Good). Flow 190 F.) 4 hrs None (Good).

1 Tackiness or film transfer aiter 4 hours dryingls determined manu ally. (Spec. MIL-C-16173 method.)

2 Determined by mechanically abusing the coating at 0 F. with a scratch'tool consisting'ofd paralleirazor blades mounted M apart. 54,.fiaking is very poor adhesion and Mia" flakingor less 13 considered satisfactory. (Spec. AXS-GZB) 3 Determined by storinga' coated steel panel at 190 F. ior i' hours and noting signs of coating flow. (Spec. AXE-673) TABLE II Thin film rust preventive:

Gelling tendency 1 Base B 25.4 (very poor). Base B+5 wtppercent of wax glyoxalidine 2.3 (good):

Percent increase in fl1m"thickness after the compound is stored for 5 da sat room temperature.-

Base B: 3%) wt. percent oxidized asphalt (220-235 F. S P

wherein R is a monovalent saturated hydrocarbon radical having from 40-to carbon atoms and wherein x is a number of from 1 to 2.

Other additive materials such as plasticizers, wetting agents, and the like, may be blended with this base material to improve special qualities thereof.

What is claimed is:

1. The method of improving the storage stability of cutback asphalt-base thin film rust preventive compositions which comprises blending with said compositions a minor but viscosity-stabilizing amount of a wax amine compound having the formula N-CH:

wherein R is a monovalent saturated hydrocarbon radical having from 40 to 80 carbon atoms and wherein x is a number of from 1 to 2.

2. A method according to claim 1 Wherein said composition comprises a blend of from about 30 to 70 percent of an oxidized asphalt having a softening point between about 180 and 235 F. with from about 70 to 30 percent of a petroleum solvent naphtha.

3. A thin film rust inhibiting asphaltic composition consisting essentially of a cutback asphalt consisting of a blend of from about 30% to about 70% of an asphalt selected from the group consisting of oxidized asphalts and oxidized and reduced asphalts with from 70% to 30% by weight of a petroleum solvent inhibited against viscosity increase during storage with a minor but viscosity-stabilizing amount in the range of l to 5 Weight percent of a wax amine compound having the formula N-CH: RC

wherein R is a monovalent saturated hydrocarbon radical having from to 80 carbon atoms and wherein x is a number of from 1 to 2.

4. A rust inhibiting composition according to claim 3 wherein R is a monovalent saturated hydrocarbon radical containing about carbon atoms and wherein x is 1.

5. A rust inhibiting composition according to claim 3 wherein from 1 to 5 wt. percent of the wax amine compound is used.

6. A thin film rust inhibiting composition which consists of about 30% to about by weight of an oxidized asphalt having a softening point between about 180 and 235 F. and about 70% to about 30% of a petroleum solvent naphtha having a final boiling point within the range of from to F. and a mid-boiling point within the range of from about 300 to 350 F. containing combined therein from 1.0 to 5.0 wt. percent of a wax glyoxalidine having the formula wherein R. is a monovalent saturated hydrocarbon radical containing about 50 carbon atoms and wherein x is 1.

References Cited in the file of this patent UNITED STATES PATENTS 2,759,840 Crews et a1. Aug. 21, 1956 2,766,132 Blair et a1. Oct. 9, 1956 FOREIGN PATENTS 637,758 Great Britain May 24, 1950 p 4 UNITED STATES PATENT' ECi'FFICE CERTIFICATE OF CORRECTION Patent No. 2,860,996 November 18, 1958 Michael J. Furey It is hereby certified that error appears in the -printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line '7, for "moree" read u more column 6, line 14, for "final boiling" read flash Signed and sealed this 9th day of June 1959.

(SEAL) Attest:

KARL H. AXLINE Attesting ()fficer ROBERT C. WATSON Commissioner of Patents 

1. THE METHOD OF IMPROVING THE STORAGE STABILITY OF CUTBACK ASPHALT-BASE THIN FILM RUST PREVENTIVE COMPOSITIONS WHICH COMPRISES BLENDING WITH SAID COMPOSITONS A MINOR BUT VISOCOSITY-STABILIZING AMOUNT OF A WAX AMINE COMPOUND HAVING THE FORMULA 